eInsert the needle slightly to one side of the midline at 90 dearees to the surface of the bone,as bone mamrow tends to be less cellular at the midline(fiqure3) .The remainder of the stemal aspiration technique is similarto that used for the iliac crest.As noted above,a biopsy at this site is contraindicated. Tibial aspiration-Tibial aspiration should be undertaken only in children younger than 12 to 18 months old [14]. .The site of aspiration should be in the upper third of the bone and slightly edial to the ante et. om th aat the d of the medial surface of the tibia,just below the tibial tubercle [41]. .Angle the needle posterolaterally.Once the needle is secured into the bone,aspiration should be attempted,since the "give"typically felt on aspiration of marrow from the iliac crest is characteristically absent at this site .Remove the stylet.Attach a 10 mL syringe and pull back the barrel with some force in order to aspirate sufficient material from the marrow cavity [141 Surgical biopsy-Bone marrow examination may be obtained by an incisional biopsy at a number of different bony sites.An appropriate site is usually determined by prior examination of the patient or by the appropriate radiologic method(eg,CT scan,MRI).As an example,when investigating a patient with possible metastati c cancer or m ultiple myeloma itis mpor choose an area where there is clinical or radiologicevidence for potential bone marrow invasion [3].Such procedures may be performed under CT guidance,as required.Bone marrow may also be obtained at the time of a related surgical procedure(eg,resection of a deep lymph node,splenectomy) PREPARATION OF SAMPLES Slides of the aspirated marrow may be prepared at the bedside.or the aspirated material may be anticoagulated and smeared at a later time.Depending on the clinical scenario,up to nine bone marrow direct smears may be prepared When performed at the bedside,slides should be prepared rapidly to avoid clotting.Adequacy of the specir nen is determined by the presence of "spicules,"which appear as fatty droplets,granules,or small chunks of bone which allow assessment of marrow cellularity.Spicules tend to concentrate at the feathered edge when a smear of the bone marrow is made. Materials-The necessary materials for preparation of aspirate smears include: ●Insert the needle slightly to one side of the midline at 90 degrees to the surface of the bone, as bone marrow tends to be less cellular at the midline (figure 3). ●The remainder of the sternal aspiration technique is similar to that used for the iliac crest. As noted above, a biopsy at this site is contraindicated. Tibial aspiration — Tibial aspiration should be undertaken only in children younger than 12 to 18 months old [14]. ●The site of aspiration should be in the upper third of the bone and slightly medial to the anterior crest, from the flat triangular area at the proximal end of the medial surface of the tibia, just below the tibial tubercle [41]. ●Angle the needle posterolaterally. Once the needle is secured into the bone, aspiration should be attempted, since the "give" typically felt on aspiration of marrow from the iliac crest is characteristically absent at this site. ●Remove the stylet. Attach a 10 mL syringe and pull back the barrel with some force in order to aspirate sufficient material from the marrow cavity [14]. Surgical biopsy — Bone marrow examination may be obtained by an incisional biopsy at a number of different bony sites. An appropriate site is usually determined by prior examination of the patient or by the appropriate radiologic method (eg, CT scan, MRI). As an example, when investigating a patient with possible metastatic cancer or multiple myeloma, it is important to choose an area where there is clinical or radiologic evidence for potential bone marrow invasion [3]. Such procedures may be performed under CT guidance, as required. Bone marrow may also be obtained at the time of a related surgical procedure (eg, resection of a deep lymph node, splenectomy). PREPARATION OF SAMPLES Slides of the aspirated marrow may be prepared at the bedside, or the aspirated material may be anticoagulated and smeared at a later time. Depending on the clinical scenario, up to nine bone marrow direct smears may be prepared. When performed at the bedside, slides should be prepared rapidly to avoid clotting. Adequacy of the specimen is determined by the presence of "spicules," which appear as fatty droplets, granules, or small chunks of bone, which allow assessment of marrow cellularity. Spicules tend to concentrate at the feathered edge when a smear of the bone marrow is made. Materials — The necessary materials for preparation of aspirate smears include: